Certifications
Free From
Highlights
Cruelty-free
Leave-in treatment
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Best Non-Toxic Straighteners Smoothing Treatments
We vetted straighteners & smoothing treatments against the Welpr Standard and here are our top picks.
Cofounder & Product Curator
Medical Reviewer, PhD
Here's what we look for:
- Simple formulations using fully natural or safe synthetic ingredients
- No parabens, PEGs, phthalates, harsh sulfates, BHA/BHT, artificial dyes, formaldehyde or formaldehyde releasers, or undisclosed synthetic fragrance (unless certified safe)
- Minimal, necessary preservatives only
- Trusted third-party certifications when available
- Transparent sourcing, ingredients, and manufacturing practices
Best Non-Toxic Straighteners Smoothing Treatments
On Welpr, terms like "non-toxic," "safer," "cleaner," "healthier," and "vetted" are editorial labels based on our own standard for product assessment. They are not guarantees, certifications, or medical claims. Learn more.
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Certifications
Free From
Highlights
Vegan
Cruelty-free
Made in USA
Recyclable packaging
Refillable
Leave-in treatment
For All hair types
Heat protection
Certifications
Free From
Highlights
Vegan
Cruelty-free
Made in USA
Pregnancy safe
Breastfeeding safe
Recyclable packaging
Refillable
Leave-in treatment
For All hair types
Free From
Highlights
Heat-activated treatment
For All hair types
Certifications
Free From
Highlights
Vegan
Cruelty-free
Made in USA
Pregnancy safe
Breastfeeding safe
Recyclable packaging
Treatment oil
For Frizz control
Lightweight
How to Swap to Non-Toxic straighteners & smoothing treatments:
Here's how to swap to non-toxic straighteners & smoothing treatments:
What to know about straighteners and smoothing treatments
Hair straightening and smoothing treatments are designed to change your hair's texture, often using strong chemical formulations that sit on your hair and scalp for extended periods. Because these products involve prolonged scalp contact and are sometimes applied with heat (which can increase absorption and release fumes), the ingredients matter more than in a typical rinse-off product.
- Many conventional smoothing treatments rely on formaldehyde-releasing ingredients, harsh preservatives, or synthetic fragrances to achieve results.
- Even products labeled "formaldehyde-free" can contain ingredients that release formaldehyde when heated, so the full formula matters.
Review the treatments you already use
Check the ingredient labels on any straightening or smoothing products you currently have. Use the Welpr Personal Care and Cosmetic Scanner to take a picture of the ingredient list and see what gets flagged.
- Look for "fragrance," "parfum," methylene glycol, or any ingredient you don't recognize — the scanner can help you sort through these quickly.
- If you use both an at-home smoothing product and a salon treatment, prioritize checking the one you use most often or leave on longest.
Use your current treatment more safely
If you're finishing up a product before switching, small changes during application can reduce what your scalp absorbs and what you breathe in. This is especially important for treatments applied with heat.
- Apply in a well-ventilated space — open windows or turn on a bathroom fan, and keep ventilation going for at least 15 minutes after you finish.
- Avoid applying treatments directly to your scalp; focus on the mid-lengths and ends of your hair when possible.
Choose cleaner replacements
Look for straightening and smoothing treatments with simple, transparent ingredient lists. The best options skip synthetic fragrance, formaldehyde-releasers, harsh preservatives, and unnecessary additives while still delivering results.
- Prioritize products that are fragrance-free or scented only with essential oils, and look for certifications like EWG VERIFIED™ or MADE SAFE® as a helpful starting point.
- Click the button above to shop Welpr Approved straightener and smoothing treatments.
Camille May
Cofounder & Product Curator
Camille May is the co-creator of Welpr and a guide for clean living. After selling her last company in the health food space, she went non-toxic while working to heal an autoimmune condition....
Olushola M. Awoyemi
Medical Reviewer, PhD
Olushola M. Awoyemi (aka Shola) is a board-certified toxicologist and a research scientist with a PhD in Environmental Toxicology. Shola's long-term ambition is to be recognized as a world-renowned expert in toxicology,...