This comparison is written by Aurabiōm, the maker of Legacy Youth Elixir. It draws on product information and published research, not a hands-on test of the two products together. The hero image illustrates the two formats; it does not show samples from either brand.
Choose the role before the ingredient count
A serum and a moisturizer can share ingredients without doing the same job in a routine. Adding a serum lets you keep the moisturizer whose finish and comfort already suit you. Choosing a peptide moisturizer combines those roles in one step, but also means choosing that moisturizer's texture.
Add a serum
Legacy Youth Elixir fits a routine where you want a separate peptide step. You retain control over the moisturizer used afterward; the tradeoff is an extra layer.
Combine two roles
OS-01 FACE fits a routine where you want a peptide within the moisturizing step. The tradeoff is that its formula and finish must suit you as a moisturizer, too.
If your current routine already works well, neither product is an essential extra purchase.
This distinction matters more than finding the longest ingredient list. Six peptides are six named ingredients, not six times the result. A formula's concentrations, stability and overall composition also matter, and an ingredient list does not tell you all of those things.
What is different in the formulas?
Legacy Youth Elixir contains six peptides, including Copper Tripeptide-1, also known as GHK-Cu, and Acetyl Hexapeptide-8. Its label also lists glycerin and four forms of hyaluronic acid alongside ingredients such as resveratrol. That makes it a multi-peptide option for someone who wants these ingredients in a separate serum step.
OneSkin OS-01 FACE lists its proprietary peptide as Decapeptide-52. Its moisturizing base includes glycerin, squalane and plant oils, with hyaluronic acid, niacinamide and allantoin. The useful contrast is a serum built around a peptide blend versus a moisturizer built around OneSkin's signature peptide.
The surrounding formula deserves attention, too. For example, Legacy Youth Elixir's label includes ethyl alcohol; the current OS-01 FACE list does not. If you already know an ingredient does not agree with you, use that history when choosing. A single ingredient's presence or absence cannot predict how everyone will experience a finished formula.
Aurabiōm's label also lists Diamond Powder, Hydroxypropyl Cyclodextrin, Lecithin and Phospholipids. If delivery technology is part of your buying decision, our guide to peptide delivery explains what formulation can change. The label is a starting point for that question, not a measurement of how much peptide reaches a particular skin layer.
What does the research help you decide?
OneSkin has a useful advantage for a buyer who prioritizes published research on a peptide-containing formula: a 2024 split-face study tested OS-01 in 22 participants for 12 weeks. Each person applied the peptide formula to one side of the face and the same base without the peptide to the other. This helps separate the contribution of the peptide from the moisturizing base.
The OS-01 side showed a greater reduction in water escaping through the skin, a measure of barrier function. Both sides improved on several appearance measures. The study was small and included OneSkin-affiliated authors; it compared OS-01 with its base, not with Legacy Youth Elixir.
Our Legacy Youth Elixir ingredient references answer a different question: why particular ingredients are included. They should not be read as a trial of the entire serum against OS-01 FACE. The source set used here contains no direct trial of these two products against each other.
For your choice, that means published formula research is a reason to favor OneSkin if that is your priority. A multi-peptide serum that fits around a moisturizer you already like is a reason to consider Legacy Youth Elixir. Those are different reasons, and either can be useful without inventing a head-to-head winner.
Compare the cost of the routine
At the U.S. one-time prices checked on October 12, 2026, one Legacy Youth Elixir bottle is $99 and the OS-01 FACE starter set is $117. Subscription, refill and promotional offers differ; check the selected option before buying.
The $18 difference is not the whole budget decision. If you add Legacy Youth Elixir and continue buying your current moisturizer, both remain part of your routine cost. If OS-01 FACE replaces that moisturizer, compare the replacement cost with what you currently spend. Bottle price alone cannot establish cost per use because application amounts and how quickly you finish each product can differ.
Make one deliberate change
Choose Legacy Youth Elixir when you want to keep a moisturizer you enjoy and add a multi-peptide serum. Use 2–3 pumps on clean, dry skin every morning. The simple routine guide shows where that step sits.
Choose OS-01 FACE when the moisturizer is the step you want to replace, or when the published peptide-formula study is an important part of your decision. Follow OneSkin's directions for that product.
You do not need to buy both to make a thoughtful choice. Pick the change that solves the problem you actually have: an added serum, a different moisturizer, or no change to a routine that already suits you.
Sources & References
2. OneSkin. OS-01 FACE product information. Ingredients and U.S. starter-set price checked October 12, 2026.
3. Zonari A, Brace LE, Harder NHO, et al. Double-blind, vehicle-controlled clinical investigation of peptide OS-01 for skin rejuvenation. Journal of Cosmetic Dermatology, 2024. Study.