What counts as an add-on
Standard IVF has a core set of steps: stimulation, egg collection, fertilisation, embryo culture and transfer. An add-on is an extra test, technique, drug or procedure layered on top, usually at extra cost, with a claim that it will help. Examples include embryo imaging systems, special culture fluids, endometrial tests, immune treatments and genetic screening of embryos.
Some extras have a clear medical reason in particular situations. ICSI is standard for serious sperm problems, for example. The difficulty is that the same extras are often offered much more widely than the evidence supports. Telling the two situations apart is the whole skill.
How the HFEA rates add-ons
The Human Fertilisation and Embryology Authority (HFEA) regulates fertility clinics in the UK. Its expert committee reviews the published evidence for common add-ons and gives each a rating (HFEA, last reviewed September 2026). The ratings mainly answer one question: does this add-on increase the chance of having a baby?
| Rating | What it means |
|---|---|
| Green | High-quality evidence shows it improves the treatment outcome |
| Yellow | Unclear: good-quality studies disagree with each other |
| Grey | Not rated, because there is not enough good-quality evidence to judge |
| Black | Good-quality evidence shows it has no effect on the outcome |
| Red | Possible safety concerns, and/or evidence that it may reduce effectiveness |
Two details are easy to miss. First, some add-ons carry extra ratings for other outcomes, such as miscarriage, or for specific patient groups. Second, the HFEA says a red safety rating flags a concern but does not automatically mean the add-on is unsafe for you. It means you should discuss it with your clinic in light of your own history.
Where the common add-ons sit
These are the HFEA's ratings for its main outcome when we reviewed the page in October 2026. Ratings can change as new studies are published, so check the HFEA page before making a decision.
| Add-on | HFEA rating |
|---|---|
| Androgen supplementation | Grey |
| Assisted hatching | Grey |
| Elective freeze-all cycles | Yellow |
| Endometrial receptivity testing | Red |
| Endometrial scratching | Yellow |
| Hyaluronate-enriched transfer medium (e.g. "embryo glue") | Yellow |
| Immune treatment: intralipids | Grey |
| Immune treatment: IVIG | Red |
| Immune treatment: steroids | Red |
| IMSI (high-magnification sperm selection) | Grey |
| Intrauterine culture | Grey |
| Microbiome testing | Grey |
| PICSI, for male-factor infertility | Black |
| Platelet-rich plasma (PRP) | Red |
| PGT-A (embryo chromosome screening) | Red |
| Time-lapse imaging and incubation | Black |
| Sperm DNA fragmentation testing | Grey |
One technique has left the list: the HFEA explains that egg activation using calcium ionophore stopped being rated as an add-on in October 2023, because it is now authorised for use in selected patients only.
Several of these have their own detailed articles on this site. Our review of PGT-A, ERA and assisted hatching goes deeper into three of the most commonly sold extras, and the PGT-A evidence debate lays out both sides of the most argued-over one.
Reading the colours sensibly
Grey is not the same as "doesn't work"
Grey means the evidence is too thin to judge. An add-on can be grey because it has barely been studied, or because the studies are too small or poorly designed. Either way, paying for a grey add-on means paying for something nobody can yet say helps.
Yellow means the studies disagree
Yellow sits between promising and disproven. Good-quality trials exist, but they point in different directions. Endometrial scratching and elective freeze-all cycles are examples. A yellow add-on deserves the most careful conversation, because a clinic can quote a supportive trial while another trial says the opposite. Ask which studies the recommendation rests on, and whether they included patients like you.
Black is a clear answer
Black means good studies looked and found no effect on the chance of a baby. Time-lapse imaging is an example. A clinic may still use a time-lapse incubator for its own workflow, which is different from charging you extra on the promise of better odds.
Red needs a direct conversation
Red covers safety concerns or evidence of possible harm to your chances. For PGT-A, it is worth knowing that the ASRM Practice Committee (2024) also concluded that routine testing for all IVF patients cannot be recommended, while noting it may be reasonable to discuss in some situations.
The add-on that is not on the list: routine ICSI
ICSI, injecting a single sperm into each egg, is essential for many couples with male-factor infertility. It is also used far more widely than that. The ASRM Practice Committee's 2026 opinion advises against using ICSI routinely when there is no male-factor problem. It specifically lists unexplained infertility, low egg numbers, diminished ovarian reserve, advanced maternal age and PGT-A as situations where ICSI is not recommended without a male factor. It also advises weighing ICSI's added cost, because evidence of a live-birth benefit in these groups is limited or absent.
The same opinion names a few non-male-factor situations where ICSI may help, such as testing embryos for a single-gene condition (PGT-M), previous poor or failed fertilisation with conventional IVF, and previously frozen eggs. If ICSI is on your treatment plan, it is fair to ask which reason applies to you.
An illustrative way to weigh one add-on
This is a made-up example, not real prices or odds. Imagine your budget covers either two standard cycles, or one cycle plus a bundle of extras that costs as much as a second cycle. If the extras have grey or black ratings, the realistic comparison is a known second attempt against an unproven boost to the first. Framing it this way, as what you would give up, often makes the decision clearer than looking at the add-on on its own.
A cost lens that is easy to overlook
The HFEA makes a practical point for self-funded patients: weigh the cost of several standard cycles against one expensive cycle loaded with unproven extras. Add-ons do not just add to one bill. They can use up the money that would have paid for another attempt.
The HFEA also refers to a 2023 consensus statement that treatments without strong evidence of safety or effectiveness should only be offered within research, and that patients should not be charged extra to take part in research.
Questions to ask about any add-on
- Why are you recommending this for me specifically, rather than for patients in general?
- What is the best evidence that it increases the chance of a live birth, not just a positive test?
- How is it rated by the HFEA, and do you agree with that rating?
- What does it cost, and what is my plan if I decline it?
- Are there any risks, including the risk of losing embryos or delaying transfer?
- Is this being offered as part of a research study? If so, why am I paying for it?
For patients comparing clinics abroad
Package prices sometimes bundle add-ons in without listing them separately. Ask for an itemised quote showing what is standard and what is extra, and ask the same add-on questions of every clinic you compare. Clinics outside the UK are not bound by HFEA ratings, but the evidence behind each rating does not change at the border.
The Takeaway
Treat every add-on as optional until someone shows you good evidence that it raises your own chance of a baby. Use the HFEA's ratings as a starting point, ask the questions above, and protect your budget for the parts of IVF that are known to work.
Frequently asked questions
Are any IVF add-ons proven to work?
When we checked in October 2026, none of the add-ons on the HFEA's list had a green rating for increasing the chance of a baby. Some may still help particular patients, and some techniques, like ICSI for male-factor infertility, are standard care rather than add-ons in that setting.
Does a red HFEA rating mean an add-on is dangerous?
Not automatically. The HFEA says red flags a potential safety concern or evidence that it might reduce effectiveness, and that you should discuss it with your clinic in the context of your own medical history.
Why would a clinic offer something without strong evidence?
A clinic may believe an extra could help before trials have settled the question, and patients understandably ask for anything that might improve their odds. That is why the HFEA encourages patients to ask for the evidence behind anything they are offered.
Is ICSI an add-on?
It depends on why it is used. For male-factor infertility it is a core treatment. For non-male-factor infertility, ASRM's 2026 opinion says routine use is not recommended, which puts it closer to an add-on.
Do HFEA ratings apply to clinics outside the UK?
The HFEA only regulates UK clinics, so its ratings are not binding elsewhere. They are still a useful, independent summary of the evidence wherever you have treatment.