The "worldwide shortage" of HRT testosterone Primoteston and now Sustanon has left lots of Australian trans and nb folks little choice but to switch to the longer-acting Reandron. Are there any potential health problems with switching? Your endo and your doc will probably say that problems are highly unlikely. But if your gut is still uneasy about the switch then let's look a little deeper:
What is a Testosterone ester?
The testosterone molecule itself is the same between different medications -- it's the esters that are different. Esters are combinations of hydrogen, oxygen, and carbon atoms attached to the testosterone itself. They have to be broken down by the body to "release" the testosterone. The combination of esters determines the half-life of the testosterone, or how long it remains in the body. This is super important to maintain "stable levels" between shots.
This ester is metabolised in roughly 4 - 5 days. It remains in the body for 2 weeks -- depending on your body weight, metabolism, and lots of other factors.
Propionate is a much faster ester which can peak in the blood within hours and is metabolised over about 3 days. Because the levels peak faster than enanthate, there is a higher risk of the testosterone being converted into estrogen and increased DHT -- translation: unwanted side effects. In theory, the other esters in the Sustanon blend can keep the levels stable until the next injection, but they won't slow down that initial peak. That said, effects are personal and everyone may react differently.
Undeanoate is a much larger ester that takes much longer to be metabolised. It's also WAY MORE volume -- a Reandron shot is designed to last ~3 months, so the total volume of fluid in a generally prescribed dose (1000mL) is 4 times the amount of a pre-filled Primoteston syringe (250mL).
If we look at all the different esters, you can see that the undecanoate ester from Reandron has a lot of extra stuff attached to the testosterone molecule:
Sustanon contains a peanut oil base, whereas Primoteston and Reandron use (the traditionally less allergenic) castor oil, with a benzyl alcohol.
TLDR: The three different types of T available in Australia all contain different esters, which probably shouldn't but anecdotally do have different effects on the body.
Here's what I'm personally Concerned about:
1. Side effects! I struggled with mood swings, weight fluctuation and cystic acne during early transition and I'm not keen to through any of that again. In theory, that shouldn't be a problem because the core testosterone is the same but I've heard enough anecdotal accounts from friends and clients to be a little worried.
2. Allergic reactions if I switch from castor oil based Primoteston to peanut oil based Sustanon. I'm not allergic to peanuts but I could still react to the concentrated peanut oil base. I'd also like to keep my immune system chill, even if I stick to a castor oil based Reandron or Primoteston.
3. Stress. I know I'm not alone in this one -- this whole shortage situation is stressful!! Stress can set off a range of health issues including chronic illnesses, dormant viruses, mental illnesses, and just generally feeling like shit.
How I'm Helping My Body While I Switch Testosterone Medications:
1. Vitamin C to Boost Immune Function & Reduce Allergy Reactions
Vitamin C is a powerhouse of antioxidant and immune support, but it also has major roles in
Vitamin C has been shown to :
Help the immune system learn what to do (and not do) with new medications. This can help reduce the risk or strength of any allergy responses the body might launch against new T formulas and oil suspensions.
Strengthen the immune system to protect against infections while the immune system is getting used to the new medication.
Reduce the formation of scar tissue at injection sites.
Support enzymes that control gene regulation. Want to switch on those masc genes, bro? Vit C's gotta be there.
Prevent acne by reducing the presence of P. acnes bacteria and by creating collagen to strengthen the skin. 
Reduce inflammation throughout the body. Most side effects I'm concerned about occur due to uncontrolled inflammation -- in theory, vitamin C can stop them before they start. 
Most of us could use a boost of vitamin C. In fact, scurvy is making a come-back. Yikes. Luckily, you can easily increase your dietary intake by eating more red capsicum, broccoli, kiwi fruit, kale, and citrus. Vitamin C is a particularly safe nutrient to supplement in most cases. Separate doses of 250mg throughout the day, and cut back if you start to have loose stools 💩
2. Workin' On Workin' Out
Changing medical treatments can be stressful! Exercise of any kind can help the body to burn through stress hormones (the type of stress hormones that put strain on the liver, block the effects of testosterone, boost oestrogen levels...) Mood swings, be gone -- I'll be doing a Yoga with Adriene 30 Day Challenge, swimming, and weight lifting regularly while settling into my new medication. Just don't overdo it -- over-training is form of stress that'll throw your hormones out of whack, too.
TIP: Movement can also help relieve the pain from injection sites. Keep moving until the injection site soreness starts to fade. If it remains after a few days or appears out of nowhere, you may have an internal bruise -- apply ice instead of heat.
3. Positive Visualisations, Meditations & Hypnosis
Placebo effect? Maybe, but that's been proven to be super helpful, too! Here are some new beliefs I'm adopting: My body loves the new testosterone esters even more than it loved the old ones. It'll finish the work that the previous T stated. It will complete changes that I'm not completely satisfied with yet.
And here is a definitely true beliefs to remind myself of: My body knows exactly what to do with this new medication.
4. Zinc for Oestrogen Balance & DHT
I'm going to take a practitioner-quality zinc supplement 2 weeks before I switch meds, and then a low dose ongoing for at least 3 weeks.
Zinc supplementation can do a bunch of great stuff including:
Reduce the conversion of testosterone to DHT (the testosterone metabolite that is great for building muscle but also causes balding and bunch of other stuff I'd rather not experience!)
Block the enzyme that converts testosterone into oestrogen 
Support the liver to metabolise testosterone and clear out oestrogens and stress hormones 
Help the body to build new structures, like muscles and stronger bones
Strengthen the immune system 
5. Loving my Liver
Introducing a new medication can put a little extra demand on the liver. If it's overwhelmed, a sluggish liver shows up as acne, headaches, mood problems, sleep issues, slow recovery from exercise, and generally feeling like crap. To prevent this, I'll be sticking to no caffeine, no alcohol, and a balanced diet. I'm going to take some liver supporting herbs as teas (like milk thistle, dandelion root, and turmeric), and focus on liver-supporting foods like cruciferous vegetables . If things get gnarly with side effects, I'll do a liver support program... But if you're thinking of doing the same please don't go overboard, and don't do it alone -- the liver is no joke, and pushing up the wrong enzymes can result in seriously whacked out hormones.
Book in for a discovery call if you would like personalised support while you switch testosterone medications, or for any reason at all.
Be sure to subscribe to my newsletter for regular updates on my offerings, writings, and ramblings!