Rapidlash vs Grandelash – Which serum is most likely to grow your lashes

Long, thick eyelashes are incredibly fashionable right now. They make your eyes pop. Putting on falsies every day can be time-consuming and frustrating. Plus, you have to deal with taking them off and caring for them. For this reason, many people are turning to growth serums to enhance their natural eyelashes in hopes of adding length and fulness. 

Rapidlash and Grandelash are two popular brands that specialize in eyelash growth serums. They have been around for many years and they are some of the most popular brands on the market today. In this article, we will look at the ingredients and effectiveness of both brands so you can get an idea of which is right for you. I wrote about Rapidlash recently and considered whether Grandelash is safe, so check those articles out for even more info on their lash serums.

Please be aware that this article is our opinion and not to be used to make a decision about whether the products are safe for you or not. The chance of experiencing side effects with lash serums can depend on a number of factors but we hope this article will give you an insight into the two different products. Please consult an expert who is aware of your health condition before deciding whether to try either serum.


How Long Do They Take to Work?

As with skin or other hair serums, it takes several weeks before you can expect to see results. Rapidlash claims that you can see results in as few as 4 weeks. They do recommend using the product for 8 weeks straight before expecting any results, though. Most customers who have reviewed have used the Rapidlash serum for a few months before observing noticeable changes to the length or thickness of their eyelashes. 

Grandelash claims that results are possible in 4 to 6 weeks. Most customers who have used the product say they noticed results in about 3 months of using the product regularly. Keep in mind that with both serums, consistent usage is key to seeing progress, as your eyelashes will return to their original length and thickness when you stop using the serum. 

Ingredients and Formula

While Rapidlash and Grandelash both seek to give you longer, fuller lashes, they use different basic formulas to accomplish that goal. 

The primary ingredients advertised in Rapidlash’s serum are: 

  • lsopropyl Cloprostenate – The key ingredient likely to promote lash growth, this is a prostaglandin analogue and a strong ingredient that has the potential to cause side effects. Most lash serums use prostaglandin analogues in their formulas.
  • Polypeptides- The goal of these polypeptides is to strengthen your lashes to make them more resistant to breakage
  • Biotin- Rapidlash includes Biotin (in the form of Pro-vitamin B7/Vitamin H) in their formula because it can help your lashes stay healthier
  • Panthenol- Panthenol (in the form of Vitamin B5) is included to help lock moisture into your lashes which can improve the appearance of your eyelashes
  • Amino Acids- Amino acids can supplement the protein structure of your eyelashes and make them look healthier
  • Soybean Oil- Soybean oil has a variety of vitamins that can be good for your lashes. It can help your eyelashes have more shine and gloss
  • Pumpkin Seed Extract- Rapidlash claims that the addition of pumpkin seed extract will help enhance your lashes and improve their balance

On the other hand, the primary ingredients touted in Grandelash’s serum are: 

  • Amino Acids- Grandlash includes L-Proline. These amino acids are designed to help fortify your lashes and give them a healthier appearance
  • Hyaluronic Acid- This acid conditions the eyelashes, making them softer and more hydrated
  • Vitamin E- Grandlash uses Vitamin E as Tocopheryl Acetate to help promote overall lash health

While the companies place importance on different ingredients, it is important to note that there is some overlap between the serums. Both use amino acids. Similarly, Grandlash advertises Hyaluronic acid, which is included in the pumpkin seed extract that Rapidlash use in their lash serum formula. Hyaluronic acid is being formulated into so many hair products and lash serums over the past few years.

This is because hyaluronic acid can held hold in moisture in your strands of hair. This won’t help them grow faster but can potentially help your lash hairs to last longer and not fall out so easily.

Side Effects 

The most commonly reported side effects of using Rapidlash’s eyelash serum are: 

  • Eye irritation- this is common if you are not applying the serum carefully. Some users reported eye irritation even with careful application, though. Stop using Rapidlash if your eyes become irritated.
  • Skin darkening- some consumers of Rapidlash have reported slight skin darkening around the eyes. This may be due to the serum making contact with the skin during application. It appears to be a temporary side effect. 

The most commonly reported side effects of using Grandelash’s eyelash serum are: 

  • Eye irritation- this is similar to the irritation experienced by users of Rapidlash’s serum. Stop using the serum if your eyes become irritated or painful. 
  • Eye pain- some users have found their eyes feel tender or painful while using Grandelash’s serum. 
  • Skin darkening- the same skin darkening experienced by users of Rapidlash’s serum is reported in users of Grandelash’s serum. 

Likely Results

Consumers who use Rapidlash most commonly report noticing that their lashes are thicker and less brittle. Many feel their lashes are longer as well, so they may not use as much mascara. Reviewers do say if you want your lashes to look like you are wearing falsies, this product will not give you that much additional volume. 

Consumers using Grandelash also report thicker lashes. Fewer customer reviews mention noticeably longer lashes. Similarly, do not expect falsie-like volume and length with this formula. 

Eyelash serum buyers guide

Here are some tips and things to consider when you are comparing which of these 2 lash serums to use. Deciding whether to use an eyelash growth serum can be a big decision because of the different choices, ingredients and potential side effects. You should consult with an expert who knows your health situation before trying out a lash serum.

Lash growth serum review criteria


There are some ingredients you should look out for if you want the best chance of your lash serum working and not causing too many side effects. Prostaglandin analogues are one of the only ingredients proven to have an effect on lash growth. Another lash serum manufacturer called Latisse use Bimatoprost, but you can’t buy it in the shops which is why both Grandelash and Rapidlash don’t use Bimatoprost.

Rodan and Fields Lash Boost and Babe lash both use synthetic prostaglandin analogues which have a similar but less proven effect on your lashes. Most lash serum brands use a combination of Biotin, peptides, hyaluronic acid, camellia extract, , keratin and elastropin.

With lash serums, you can’t tell how effective they are going to be by only looking at the ingredients. There is often very little research around lash growth ingredients. Instead, look at what other users experience and try to find studies involving these ingredients that might give you an idea of how they work.

As you can see Babelash and Grandelash both have similar ingredients and results are also similar. The main difference is that Babelash use Vegan ingredients and Grandelash don’t. However Grande lash don’t use Parabens.

Safety and side effects

Side effects are the most concerning factor about lash serums, but you have to be aware of the small chance of experiencing them. These lash serums are applied close to your eyes and near some very sensitive areas of skin. Your eyes themselves and the skin around them is very easy to irritate. Be sure to seek professional advice and only apply a small test sample before gradually increasing how much serum you apply to reduce the chance of any problems.

Final thoughts about Grandelash and Rapidlash

Grandelash and Rapidlash have very similar formulas and side effects. Both have similar reviews in terms of reported results. Rapidlash does have more touted active ingredients to help fortify the lashes, and more reviewers noted additional length and thickness when using Rapidlash than when using Grandelash. 

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