OS-01 Prep
OS-01 Prep
Product Description
Product overview
A gentle daily gel cleanser formulated by longevity scientists to remove impurities, lightly exfoliate, and prime skin for up to 2.2x better absorption of the OS-01 peptide. Sulfate-free, fragrance-free, and dermatologist tested for all skin types including sensitive skin.
Boosts Peptide Absorption by 2.2x
Lab-tested on ex vivo human skin samples to increase OS-01 peptide penetration into the dermis by up to 2.2 times when used before OS-01 FACE.
Texture & feel
SENSORYBoosts Peptide Absorption by 2.2x
Lab-tested on ex vivo human skin samples to increase OS-01 peptide penetration into the dermis by up to 2.2 times when used before OS-01 FACE.
Barrier-Friendly Cleansing
Uses mild sugar-derived surfactants instead of harsh sulfates to cleanse without disrupting the skin's natural lipid barrier or microbiome.
Gentle Exfoliation
Prickly pear extract and Breu Branco resin provide light physical and antioxidant exfoliation to slough away dead skin cells without irritation.
Hydration-Boosting AQP3
When paired with OS-01 FACE, shown to increase aquaporin-3 (a key hydration biomarker) by up to 40% in lab studies on human skin.
Safety & compatibility
SAFEFree from retinoids, salicylic acid, hydroquinone, chemical sunscreens, and parabens. All ingredients are considered safe for use during pregnancy and breastfeeding. Always consult your doctor.
Contains no oils, fatty acids, esters, polysorbates, or ferments that feed Malassezia yeast. Safe for fungal acne-prone skin.
Oil-free gel formula with no pore-clogging ingredients. Rated 0 on the comedogenic scale. Will not clog pores.
Dermatologist tested and formulated without fragrance, sulfates, alcohol, or common irritants. Gentle enough for reactive and rosacea-prone skin.
Safe to use alongside retinol, vitamin C, AHAs, BHAs, and niacinamide. As a rinse-off cleanser, it does not interfere with leave-on actives applied afterwards.
Vegan, cruelty-free, and available in eco-friendly refill pouches. Free from 15+ categories of potentially harmful ingredients.
Ingredient breakdown
INGREDIENTSSodium Grapeseedamidopropyl PG-Dimonium Chloride PhosphateProven
A powerful grape seed-derived antioxidant conditioning agent that provides 50 times the antioxidant power of vitamin C or E. Helps protect skin from free radical damage during cleansing.
- Function: Antioxidant conditioning agent derived from grape seeds
- Benefit: Protects against oxidative stress while cleansing
- Note: Unique to premium formulations; rarely found in drugstore cleansers
Hydrolyzed Opuntia Ficus-Indica Flower ExtractPromising
Prickly pear cactus flower extract that provides gentle exfoliation, removes dead skin cells, and soothes irritated skin. Rich in flavonoids that help prevent oxidative stress and aid in sunburn recovery.
- Function: Gentle exfoliant and antioxidant
- Benefit: Promotes cell turnover without mechanical abrasion
- Source: Derived from prickly pear cactus (Opuntia ficus-indica)
Breu Branco ResinPromising
An Amazonian tree resin that acts as an antioxidant exfoliant, sequestering free radicals while providing anti-inflammatory and anti-irritating properties. Helps prep skin for better product absorption.
- Function: Antioxidant exfoliant
- Benefit: Neutralizes free radicals and reduces inflammation during cleansing
- Source: Protium heptaphyllum tree resin from the Amazon
Niacinamide (Vitamin B3)Proven
A well-researched conditioning ingredient that improves skin texture by promoting protein synthesis at the epidermal layer. Brightens, strengthens the skin barrier, and has anti-inflammatory properties.
- Function: Skin conditioning, brightening, anti-acne
- Research: Extensively studied for improving skin barrier function and reducing inflammation
- Bonus: Also acts as a humectant to help maintain skin hydration
Lonicera Japonica (Honeysuckle) Flower ExtractPromising
Japanese honeysuckle extract with natural antioxidant, antibacterial, and detoxifying properties. Soothes irritated skin while providing gentle antimicrobial protection.
- Function: Soothing, antimicrobial, antioxidant
- Benefit: Calms skin while providing natural preservation support
Arnica Montana (Arnica Flower) ExtractPromising
An anti-inflammatory botanical that stimulates microcirculation and moisturizes irritated skin. Traditionally used to reduce puffiness and calm redness.
- Function: Anti-inflammatory, microcirculation stimulant
- Benefit: Helps reduce morning puffiness and soothes redness
16 ingredients
Water, Sodium Laurylglucosides Hydroxypropylsulfonate, Cocamidopropyl Hydroxysultaine, Disodium Lauryl Sulfosuccinate, Glycerin, Sodium Hydroxypropylphosphate Laurylglucoside Crosspolymer, Sodium Grapeseedamidopropyl PG-Dimonium Chloride Phosphate, Hydrolyzed Opuntia Ficus-Indica Flower Extract, Breu Branco Resin, Caprylyl Glycol, Phenoxyethanol, Lonicera Japonica (Honeysuckle) Flower Extract, Niacinamide, Sorbic Acid, Arnica Montana (Arnica Flower) Extract, Tetrasodium Glutamate Diacetate.
Where it fits in your routine
ROUTINEUse PREP as your first step, morning and/or evening. Apply OS-01 FACE immediately after for maximum peptide absorption. Sunscreen in the AM only.
How to use
HOW TO USEDampen Your Skin
Splash your face and neck with lukewarm water to prepare the skin for cleansing.
Lather 1–2 Pumps
Dispense 1–2 pumps of PREP into damp hands and rub until a light foam forms.
Massage Gently
Using circular movements, gently massage the foam onto your face and neck for 30–60 seconds.
Rinse & Pat Dry
Rinse thoroughly with lukewarm water and pat skin dry with a clean towel. Follow immediately with OS-01 FACE for best results.
Who is it for?
WHOPerfect for you if:
- You use OneSkin OS-01 FACE and want to maximize peptide absorption
- You need a gentle, non-stripping daily cleanser
- You have sensitive, reactive, or rosacea-prone skin
- You want a sulfate-free, fragrance-free cleanser
- You are pregnant or breastfeeding and need a safe option
- You prefer clean, science-backed skincare with minimal ingredients
- You care about sustainable, refillable packaging
Consider alternatives if:
- You need a heavy-duty makeup remover (use a double-cleanse method first)
- You prefer a rich, foaming lather (PREP produces a light foam)
- You want a cleanser with strong acne-fighting actives like salicylic acid or benzoyl peroxide
- Budget is a primary concern (drugstore options exist at a fraction of the cost)
- You do not use OneSkin products and want a standalone cleanser
Skin type compatibility
SKIN TYPESOil-free gel formula cleanses without over-drying. Can be used twice daily. Helps prevent pore congestion.
Non-stripping formula with glycerin preserves moisture. Follow with a hydrating moisturizer. Once daily may be sufficient.
Balances well across oily and dry zones. Gentle enough for daily use without disrupting varied skin areas.
Dermatologist tested, fragrance-free, and formulated with mild surfactants. Ideal for reactive and easily irritated skin.
Non-comedogenic and fungal acne safe. Good for maintenance, but does not contain targeted acne actives like BHA or BPO.
Designed specifically for longevity-focused skincare. Enhances absorption of anti-aging OS-01 peptide for maximum benefit.
Results timeline
WEEK 6–12Immediate Clean Feel
Skin feels thoroughly cleansed yet comfortable and hydrated. No tightness, dryness, or residue after rinsing.
95% noticed immediatelySmoother, Softer Texture
Gentle exfoliation begins to slough away surface dead skin cells. Skin feels noticeably smoother and more receptive to products applied after.
80% noticed within 2 weeksImproved Radiance & Absorption
Skin appears brighter and more even-toned. Users report that their OS-01 FACE moisturizer absorbs more readily and feels more effective.
75% noticed within 4 weeksEnhanced OS-01 Results
Cumulative benefits of improved peptide penetration become visible. Firmer skin, reduced fine lines, and improved hydration when used consistently with the full OneSkin regimen.
87% noticed with consistent useRatings by platform
750+ REVIEWSPros & cons
BALANCEDPraised
- Scientifically proven to enhance OS-01 peptide absorption by 2.2x
- Extremely gentle — does not strip or dry out the skin
- Clean, minimal 16-ingredient formula
- Fragrance-free with no sulfates or parabens
- Eco-friendly refillable bottle and pouch system
- Suitable for all skin types including very sensitive
- Leaves skin feeling soft, clean, and refreshed without tightness
- Removes light makeup and sunscreen effectively
Criticized
- Premium price for a facial cleanser (~$49 for starter kit)
- Light foam may feel insufficient for those used to heavy foaming cleansers
- Best value is within the OneSkin ecosystem; standalone value is debatable
- Pump mechanism issues reported on some early bottles
- Not a heavy-duty makeup remover — may need double cleansing for full makeup
- Limited retail availability (mainly online and select dermatology offices)
Budget-friendly alternatives (dupes)
DUPESGentle, non-foaming cleanser with ceramides and hyaluronic acid. Excellent barrier support at a fraction of the price. Lacks the specialized exfoliating botanicals and peptide-enhancing properties of PREP, but a solid everyday cleanser for all skin types.
French pharmacy cleanser with prebiotic thermal spring water, niacinamide, and ceramides. Very gentle and suitable for sensitive skin. Missing the exfoliating and absorption-enhancing ingredients unique to PREP.
Ultra-minimal, dermatologist-recommended cleanser free from dyes, fragrance, and common irritants. Excellent for extremely sensitive skin but lacks any active botanical or antioxidant ingredients found in PREP.
Comparison with competitors
SIDE-BY-SIDEStorage & shelf life
12 MONTHS12 months after opening
Store at room temperature away from direct sunlight. Shelf life of 24 months unopened.
Refillable pump bottle (200 ml) with eco-friendly refill pouch system. Clear bottle allows you to see remaining product.
Travel size available (50 ml) which is TSA-compliant. Full size (200 ml) exceeds carry-on liquid limits.
Frequently asked questions
FAQYes. PREP contains no retinoids, salicylic acid, hydroquinone, chemical sunscreens, parabens, or other ingredients typically flagged during pregnancy. Its gentle, sulfate-free formula with mild sugar-derived surfactants and botanical extracts is considered safe for use during pregnancy and breastfeeding. However, always consult your OB-GYN or dermatologist before introducing any new product during pregnancy.
Yes. PREP is fungal acne safe. Its formula is oil-free and does not contain fatty acids, esters, polysorbates, ferments, or other ingredients known to feed Malassezia yeast. The gel cleanser uses sugar-based surfactants and botanical extracts that do not promote fungal overgrowth.
Yes. PREP is a rinse-off cleanser, so it does not interact with leave-on actives like retinol, vitamin C, AHAs, or BHAs. In fact, its gentle exfoliation and barrier-preserving formula make it an ideal cleanser to pair with potent treatment products, as it prepares the skin without compromising the barrier. Apply your actives after cleansing with PREP.
PREP is formulated for all skin types and is dermatologist tested, including for sensitive skin. It is particularly well-suited for sensitive, combination, oily, and mature skin types. Those with dry skin may want to use it once daily (PM) rather than twice. It is non-comedogenic and fungal acne safe, making it suitable for acne-prone skin as well.
You will notice an immediately clean and comfortable feel from day one. Smoother skin texture typically appears within 1–2 weeks of daily use. The main benefit of PREP — enhanced OS-01 peptide absorption — works immediately but produces cumulative visible results over 6–12 weeks when used consistently with OS-01 FACE.
PREP goes first in your routine as your facial cleanser. Use it morning and/or evening. After rinsing and patting dry, apply an optional toner, then OS-01 EYE (around the eye area), followed by OS-01 FACE on your full face and neck. In the morning, finish with sunscreen. The key is to apply OS-01 FACE immediately after cleansing with PREP to maximize peptide absorption.
No. PREP is non-comedogenic with a comedogenic rating of 0/5. It is an oil-free gel cleanser that contains no pore-clogging ingredients. OneSkin explicitly states that all their products are non-comedogenic. The formula is designed to help prevent pore congestion, not contribute to it.
PREP has a shelf life of 24 months unopened. Once opened, it should be used within 12 months. One 200 ml bottle typically lasts 1–2 months when used as directed (1–2 pumps, 1–2 times daily). Store at room temperature away from direct sunlight for best results.
Verdict: OneSkin OS-01 PREP is a thoughtfully formulated, science-backed cleanser that excels at what it is designed to do: gently cleanse skin while maximizing the effectiveness of your OneSkin routine. With only 16 clean ingredients, lab-proven 2.2x peptide absorption enhancement, and a formula safe for sensitive, pregnant, and fungal acne-prone skin, it is a premium cleanser that justifies its price point for dedicated OneSkin users. The main trade-off is cost — at ~$49, it is significantly more expensive than drugstore alternatives like CeraVe or La Roche-Posay that also cleanse gently. If you are already invested in the OneSkin OS-01 system, PREP is a worthwhile addition that genuinely amplifies your results. As a standalone cleanser without the OneSkin ecosystem, the value proposition is harder to justify.
Product Overview
Quick product notes are a great way to check if a product is free from commonly avoided ingredients by skincare enthusiasts. These preferences come about for different reasons depending on the ingredient such as personal experiences, sensitivities, health preferences & etc.
Just because a product is not free from a common preference does not mean it's a bad product! You can make a personal decision whether or not you want to use a product that contains these ingredients or not - click the labels of the preference to read more about them.
Quick Product Notes
Ever used a product that promised a certain effect but provided no results? It might not have contained any notable ingredients that could have been responsible for that promised effect. It doesn't matter what the marketing or packaging «promises» it can do, if it doesn't contain anything that can help - then the likelihood of it helping is low.
We help you identify key notable ingredients that have been shown to help with effects such as acne-fighting, brightening, UV-protection, wound healing & anti-aging to help you achieve your skincare goals smarter. Please note that different notable ingredients have varying levels of research behind them, some are extremely well proven yet some have mixed research in their efficacy.
Just because a product doesn't contain any notable ingredients doesn't mean it's bad. And a product with notable ingredients (or even many) doesn't necessarily guarantee the efficacy of the product performing these effects either. There are other factors such as ingredient quality, concentration and formulation that will ultimately determine this.
Be smart and use this as just a starting point for you to make more informed and smarter choices and compare it with reviews to see if the product is right for you
Notable Effects & Ingredients
Why are some products great for some people and horrible for others? Well everyone has different skin types and different reactions to the same ingredients.
We've identified a range of ingredients that are commonly regarded as potentially good or bad for those with Dry, Oily/Acne-Prone or Sensitive skin.
A product that contains good or bad ingredients for your skin type doesn't always flat out make the entire product good or bad for your skin. There are other factors such as ingredient quality, concentration and formulation that will ultimately determine your skins reaction.
One of the best ways to use this section is to troubleshoot products you've had bad experiences with in the past. Check if it contains any of the marked ingredients to point out suspect ingredients to avoid in the future!
Ingredients Related to Skin Types
Ingredient Safety Breakdown refers to the percentage % of ingredients in different risk categories as classified by EWG (Environment Working Group) if they are available. There are almost endless cosmetic ingredients and they are one of the few organisations globally that have assigned ratings to a lot of the more commonly used ingredients which is why we reference them.
EWG is seen by many to be more on the alarmist side in their assignment of health ratings resulting in rating ingredients as riskier than they actually are. We recommend using this a reference point rather than a strict guide of ingredient safety and to always do further research if into ingredients that you may find suspect.
Ingredient Safety Breakdown
Product ingredient list
| EWG | CIR | Ingredient Name & Cosmetic Functions | Notes |
|---|---|---|---|
| 1 |
Water
Solvent, Skin Conditioning
|
|
|
| 0 |
Sodium Laurylglucosides Hydroxypropylsulfonate
Cleansing, Emulsifying
|
|
|
| 1 |
Cocamidopropyl Hydroxysultaine
Skin Conditioning, Viscosity Controlling, Viscosity Increasing Agent, Antistatic Agent, Hair Conditioning, Sufactant, Foam Boosting
|
|
|
| 1 |
Disodium Lauryl Sulfosuccinate
Skin Conditioning, Hydrotrope, Sufactant, Foam Boosting, Foaming
|
|
|
| 2 |
Glycerin
Solvent, Perfuming, Fragrance, Humectant, Viscosity Decreasing Agent, Hair Conditioning, Skin Protecting, Denaturant, Skin Conditioning
|
Promotes Wound Healing
Hydrating
|





