Hyaluronic Acid: The Ultimate Hydration Guide
This guide provides shopping guidance only—not medical, dermatology, diagnosis, or treatment advice. For health concerns, consult a licensed professional.
What Is Hyaluronic Acid?
Despite the word "acid," hyaluronic acid isn't an exfoliant—it's a humectant. It's a naturally occurring substance in your skin, joints, and eyes that holds water. In skincare, it's prized for its ability to attract and retain moisture, helping skin look plump, hydrated, and healthy.
A single gram of hyaluronic acid can hold up to 6 liters of water. When applied topically, it draws moisture to the skin and helps maintain hydration levels. As we age, our natural hyaluronic acid decreases, which contributes to dryness and the appearance of fine lines.
Benefits of Hyaluronic Acid
- Deep hydration: Pulls moisture into the skin
- Plumping effect: Hydrated skin appears fuller, minimizing fine lines
- Suitable for most skin types: Generally well-tolerated, including sensitive skin
- Lightweight: Doesn't feel heavy or greasy
- Layers well: Works under other products without pilling
- Non-comedogenic: Unlikely to clog pores (good for oily skin)
Understanding Molecular Weights
Hyaluronic acid comes in different molecular weights, which affects how it works:
High Molecular Weight (HMW)
Larger molecules that sit on the skin's surface. Creates a hydrating film, provides immediate plumping effect, and prevents water loss. Doesn't penetrate deeply.
Low Molecular Weight (LMW)
Smaller molecules that can penetrate deeper into the skin. Provides hydration at a deeper level but may cause irritation in some people.
Multi-Weight Formulas
Many products contain multiple molecular weights to provide both surface hydration and deeper penetration. These are often labeled "multi-molecular" or list multiple forms of HA.
Sodium Hyaluronate
The salt form of hyaluronic acid. Has a smaller molecular size and penetrates more easily. Very common in products—often used interchangeably with "hyaluronic acid" on labels.
How to Use Hyaluronic Acid
The Damp Skin Rule
Apply hyaluronic acid to damp skin—not dry. Because HA is a humectant, it pulls moisture from wherever it can find it. On damp skin, it pulls water from the surface. On dry skin in a dry environment, it might draw moisture from deeper skin layers, potentially making skin feel drier.
When to Apply
Both morning and evening work. HA plays well with most other ingredients, making it versatile in any routine.
Order in Routine
- Cleanser
- Toner (if using)
- Hyaluronic acid serum (on damp skin)
- Other serums (vitamin C, niacinamide, etc.)
- Moisturizer (to seal in hydration)
- Sunscreen (AM)
The Importance of Sealing
Always follow hyaluronic acid with a moisturizer or oil. This creates an occlusive layer that prevents the water HA attracted from evaporating. Without this step, HA is less effective—especially in dry climates.
Layering with Other Ingredients
Hyaluronic acid is one of the easiest ingredients to layer:
- Vitamin C: Apply vitamin C first, then HA. See our vitamin C guide
- Niacinamide: Great pairing—both are hydrating and barrier-supportive. See our niacinamide guide
- Retinol: HA can help buffer retinol irritation. Apply HA first, then retinol. See our retinol guide
- AHAs/BHAs: Apply acids first, wait, then HA
- Moisturizer: Always follow HA with moisturizer
Product Types
Serums
The most popular format. Concentrated, lightweight, absorbs quickly. Typically 1-2% hyaluronic acid (higher isn't necessarily better).
Toners/Essences
Lighter than serums. Good for layering or as a hydrating first step. Popular in Korean skincare routines.
Moisturizers
Many moisturizers include HA. Convenient but often at lower concentrations than dedicated serums.
Sheet Masks
Provides an intense hydration boost. The mask keeps the product in contact with skin for extended absorption.
For Different Skin Types
Dry Skin
Use a multi-weight formula and always seal with a rich moisturizer. May benefit from layering multiple HA products. See our dry vs. dehydrated skin guide.
Oily Skin
HA provides hydration without heaviness—perfect for oily skin that still needs moisture. Use lightweight formulas and gel moisturizers to seal.
Sensitive Skin
Generally well-tolerated. Some very sensitive skin may react to low molecular weight HA; in that case, try high molecular weight only.
Aging Skin
Excellent for plumping fine lines. Often combined with peptides and other anti-aging ingredients. See our anti-aging guide.
Where to Shop
Hyaluronic acid products are available at every price point:
Frequently Asked Questions
What does hyaluronic acid do for skin?
Hyaluronic acid is a humectant that attracts and holds water—up to 1000 times its weight. It hydrates the skin, plumps fine lines, and gives skin a dewy, healthy appearance. It's naturally found in skin but decreases with age.
Should you apply hyaluronic acid to wet or dry skin?
Applying to damp skin is generally recommended. Hyaluronic acid pulls moisture from its surroundings—if the air is dry and your skin is dry, it may pull water from deeper layers. Damp skin gives it moisture to work with.
Can hyaluronic acid cause breakouts?
Pure hyaluronic acid is generally non-comedogenic and well-tolerated. However, some formulations contain other ingredients that might cause issues. If you experience breakouts, check the full ingredient list.
Do you need to use hyaluronic acid with a moisturizer?
Yes, ideally. Hyaluronic acid draws in moisture, but you need to seal it in. Following with a moisturizer or oil creates an occlusive layer that prevents moisture from evaporating.
Need Help Finding the Right Product?
Our AI Concierge can recommend hyaluronic acid products based on your skin type and concerns.
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