Are you only allergic to HEMA? Have you visited a dermatologist and been patch tested? Because it is extremely rare to only be allergic to HEMA.
All the patch test results that I have seen where someone reacts to HEMA, they also react to 4 or 5 other ingredients (and those that changed brand a few times, often many more). The most common allergen after HEMA is Hydroxypropyl Methacrylate (HPMA) that is used in some gels, gel polishes and also HEMA-free monomer (it is NEVER a good idea to move to HEMA-free monomer if you develop an allergy to HEMA!).
Note: HPMA is a low risk allergen when not used in combination with HEMA, or used after a HEMA allergy has developed. Many German manufactured nail products are based on HPMA and they have very low rates of allergies, especially compared to the UK.
HEMA is a cross sensitiser, also called a gateway allergen, which means it encourages allergies to other ingredients to develop - especially HPMA.
There are 13 ingredients in the standard Methacrylate patch test. These are the most common nail product allergen ingredients anyone with an allergy should definitely avoid.
So rather than asking for HEMA-free products that could contain some of these 13 allergens, those with allergies really need to be looking for hypoallergenic products that don't contain any of these 13 allergens and usually won't contain any other many other medium risk ingredients either.
There are very few brands who have developed true hypoallergenic products - in the sense that not only are low allergy risk ingredients used, but the brand also has the historical experience of the products being in the market for many years and noproven allergic responses. They are also extremely difficult and therefore expensive to develop - so most factories don't bother.
One of these brands is my company IKON.IQ Nails who started to develop hypoallergenic products in 2010.
However, it is important to set expectations. Hypoallergenic products are designed for allergy prevention, not cure. There is no 100% guarantee that someone who is allergic to many ingredients and/or whose immune system has become hyper sensitive, won't react even to these. But having said that, we have a lot of Nail Techs who came to use with allergies and have been happily using our products for years.
The best thing to do is to obtain some samples from the different hypoallergenic brands and test them for yourself, before investing in a lot of colours.