Bio-Oil vs Mederma: What's Better for Scars? (2021 ✅)

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In this post, I provide the facts on Bio-Oil vs Mederma, including key ingredients, clinical studies, customer reviews, and my personal experience.

Overall, I recommend Mederma Advanced Scar Gel for "low risk scars" like kitchen burns, minor cuts & scrapes, and small bruises, and Bio-Oil for dry skin.

For "high risk scars" like hypertrophic scars, keloids, surgery scars, and acne scars, the gold standard is a silicone gel like Aroamas (silicone is safe and clinically proven).


Bio-Oil vs Mederma

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✅ Best For: Dry Skin
✅ Key Ingredient: Mineral Oil
✅ Application: 2x Daily
❌ Clinical Evidence: Low
Side Effects: None
✅ Reviews: 83,000+
Price/Value: Very Good

New Mederma Advanced Scar Gel 50g
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Best For: Low Risk Scars
Key Ingredient: Onion Extract
Application: 1x Daily
⚠️ Clinical Evidence: Mixed
Side Effects: Itchiness, Redness
✅ Reviews: 16,000+
Price/Value: Very Good

Here's the key difference between Bio-Oil and Mederma: Bio-Oil is a blend of mineral oil, plant oils, and essential oils with low clinical evidence for scars and stretch marks while Mederma is an onion extract gel with mixed clinical evidence for scar treatment.

Here's a good analogy:

  • Bio-Oil is like Vaseline: it's good for dry skin but won't improve scars or stretch marks
  • Mederma is like Neosporin: it's good for low risk scars like burns, cuts & scrapes, and bruises, but it's not the best option for treating hypertrophic scars or keloids

For high risk scars (e.g. hypertrophic scars and keloids from surgery, accidents, or acne), the gold standard for effective scar management is a silicone gel or silicone sheet.

That's because silicone is safe, supported by decades of clinical studies, and recommended by leading dermatologists in the International Clinical Recommendations on Scar Management.

P.S. I've personally tried almost every silicone gel on the market, including ScarAway, Kelo-Cote, NewGel+, Hiruscar, Strataderm, and Azally. Check out my full review here.

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Skincare Oil

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Best For:

❌ Scars
❌ Stretch Marks
❌ Uneven Skin Tone
✅ Dry Skin
✅ Aging Skin

Key Ingredients:

⭐ Mineral Oil
⭐ Sunflower Seed Oil
⭐ Lavender Oil
⭐ Chamomile Oil
⭐ Rosemary Oil
⭐ Calendula Oil
⭐ Vitamin A and E

Key Features:

👍 2x Daily Application
👍 Light Oil Consistency
👍 Non-Comedogenic
👍 Hypoallergenic

With an astounding 83,000+ reviews, Bio-Oil has become one of the most popular skincare products in history.

But does Bio-Oil really work? 🤔

Well, I've personally used Bio-Oil on my scars in the past, reviewed the clinical studies from this company, and examined the relevant medical literature on scars and stretch marks, to help you answer this question.

In short, use Bio-Oil on dry and aging skin only.

As I'll explain later, the clinical evidence for scar treatment and stretch marks remains very low. That's why Bio-Oil is better suited as an emollient for dehydrated skin.

Mineral oil, a purified oil derived from petroleum, is the main ingredient (this explains why Bio-Oil is so cheap).

Contrary to popular belief, purified mineral oil is a safe and effective moisturizing agent, just like Vaseline.

Next, Bio-Oil uses a blend of plant and essential oils, including chamomile, rosemary, calendula, and lavender, to help nourish and hydrate your skin barrier.

Finally, PurCellin Oil, the company's "breakthrough ingredient", is actually a synthetic ester called cetearyl ethylhexanoate that's very commonly used to reduce a formula's consistency. (source: Dr. Steve Humphries)

Based on my review of the key ingredients, there's nothing special about Bio-Oil that would support its advertised effectiveness for scars, stretch marks, or uneven skin tone.

In short, Bio-Oil is a mineral oil blended with plant and essential oils plus a viscosity adjuster.

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Now, let's discuss the clinical trials provided by the manufacturer:

  1. Photobiology Laboratory of the Medical University of South Africa (2005)
  2. Department of Dermatology @ Peking University First Hospital (2012)
  3. proDERM Institute for Applied Dermatological Research (2010)
  4. proDERM Institute for Applied Dermatological Research (2017)

All studies (except #2) focused on Bio-Oil's effectiveness for reducing scars and stretch marks. However, I found a number of problems with these studies:

  • #1-3 are only available on Bio-Oil's website (not published in a peer-reviewed journal)
  • #1, 2, and 4 were only single-blinded (double-blinded is better for eliminating bias)
  • We are only told the % of patients that improved, but not the % improvement
  • We are not told what the "control group" is (most likely no treatment)

Perhaps in response to these types of criticisms, Bio-Oil authorized a second study at the proDERM Institute for Applied Dermatological Research in Hamburg, Germany.

In this study, 80 volunteers with non-hypertrophic scars and stretch marks applied Bio-Oil on treatment scars for 8 weeks (with no treatment on control scars).

Here were the final results after 8 weeks:

  • Blinded Investigator: using an Observer Scar Assessment Scale, blinded investigators (i.e. they don't know which scars were treated) found a 5% improvement in mean scar scores
  • Non-Blinded Patient: using a Patient Scar Assessment Scale, non-blinded patients (i.e. they know which scars were treated) found a 14% net improvement in mean scar scores

Overall, Bio-Oil only produced a small improvement in scar scores (5% and 14%) compared to a control of no treatment (the lowest performance benchmark).

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In addition, here's how patients responded to a follow-up questionnaire (% who agreed):

  • Long-lasting, soft, and supple skin: 93%
  • Caring effect: 87%
  • Quick absorbance: 84%
  • Improves skin appearance: 61%
  • Scars / stretch marks are less pronounced: 51%
  • No benefit to scars / stretch marks: 17%

Most patients agreed that Bio-Oil provided a hydrating effect but only 51% believed it improved their scars or stretch marks, while 17% actually said Bio-Oil had no effect at all!

Finally, here's my personal opinion of Bio-Oil based on 3+ months of usage:

  • Application: it's a light oil but feels somewhat greasy (I have oily/combo skin)
  • Results: my experience with Bio-Oil very much echoes the clinical trials - my skin felt more moisturized and it helped offset the dryness of my acne treatments, but it did not produce any improvement in my facial acne scars (mainly hypertrophic scars)
  • Side Effects: none

My Verdict: All things considered (the key ingredients, clinical studies, and my own experience), I recommend using Bio-Oil for dry skin only because there's insufficient scientific evidence to support its advertised effectiveness for scars and stretch marks.

If you're looking for a scar treatment, keep reading as I'll review Mederma in the next section.

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Advanced Scar Gel

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Best For:

❌ High Risk Scars
✅ Low Risk Scars
✅ Mild Burns
✅ Cuts & Scrapes
✅ Bruises
✅ Minor Injuries

Key Ingredients:

⭐ Onion Bulb Extract
⭐ Allantoin
⭐ Panthenol
⭐ Hyaluronic Acid

Key Features:

👍 1x Daily Application
👍 Gel Texture
👍 Mild Fragrance
🕓 4-8 Weeks (New Scars)
🕓 3-6 Months (Old Scars)

With 16,000+ reviews, there's definitely no question that Mederma is the most popular scar treatment (currently the #1 Bestseller in Scar Reducing Treatments).

But does Mederma really work on scars? 🤔

Before I provide you the answer, let me first tell you that I've personally used Mederma for 6+ months, reviewed the original clinical study in 2012 by Dr. Draelos, and consulted the medical literature on scar treatment.

In addition, I'd like you to keep in mind that everyone scars and heals differently, as genetics play a key role in how your body recovers from a wound.

For example, people with a family history of keloids are more likely to develop keloids themselves (1/3 of people with keloids have a first-degree relative with keloids).

In short, use Mederma on "low risk" scars only.

Low risk scars are defined in the International Clinical Recommendations on Scar Management as:

  1. Low Risk of Scarring: no family history of keloids, no sensitive areas like the breast/chest
  2. Low Patient Concern: you're okay with how your scar turns out, regardless the outcome

In other words, I recommend using Mederma for less serious wounds, such as mild burns, cuts & scrapes, bruises & accidents, and other minor injuries.

That's because the key ingredient in Mederma Advanced Scar Gel is onion bulb extract (a.k.a. Cepalin in Mederma's marketing materials and allium cepa in the ingredient list).

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According to the 2014 International Clinical Recommendations on Scar Management (Part 2), a highly influential research paper authored by the world's leading experts on scar treatment, there's conflicting evidence on the effectiveness of onion extract for scars.

Some studies showed positive evidence, like the original clinical trial by Draelos et al. (2012) that was sponsored by Merz Pharmaceuticals (the parent company of Mederma).

In short, this study found a statistically significant difference in scar appearance between Mederma-treated scars (test group) and non-treated scars (control group) after 4-8 weeks.

However, there's a number of major flaws with this study:

  1. Control Group: in this study, the control scars were left completely untreated. This is an extremely low benchmark and even then, the test group only surpassed the control group after 4 weeks of treatment. I'd be more convinced if the control scars were treated with at least a moisturizer as keeping scars hydrated improves wound healing.
  2. Sample Group: out of 44 participants, the vast majority were Caucasian (39), followed by African American (4), and Hispanic (1). As you might expect, the Fitzpatrick skin type was mostly I and II (both are considered very light skin tones). However, this sample almost entirely excludes ethnic skin types which creates a bias because abnormal scar formation like keloids is more common in those of African, Asian, and Hispanic descent.
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Other studies found that onion extract was no better than similar topical treatments but resulted in more frequent side effects (itchiness, redness) that caused patients to stop using it. (source: International Wound Journal, 2021)

In addition, many studies used multiple active ingredients in their formulations which made it more difficult to isolate the effects of onion extract. (source: Dermatologic Surgery, 2014)

Finally, here's my personal opinion of Mederma Advanced Scar Gel based on 6+ months of using it on my chest keloids:

  • Application: it's very easy to apply (a bit sticky but dries quickly)
  • Results: I did not see any significant improvements in scar height, thickness, or redness, however, my scars did feel slightly smoother
  • Side Effects: I experienced the occasional itchiness, but the more serious side effect was that the area where I applied Mederma turned slightly darker in color (discoloration)

My Verdict: Taking into account the key ingredients, clinical studies, and my own experience, I recommend Mederma Advanced Scar Gel for low risk scars as the medical evidence is mixed. Mederma may help minimize scars from minor injuries and accelerate the recovery process.

For high risk scars, however, I recommend using a silicone gel or silicone sheet because it's safe (no side effects), clinically proven for scar treatment, and reasonably affordable.

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Bio-Oil vs Mederma
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